CN110809810A

CN110809810A - System, apparatus and method for secure energy storage

Info

Publication number: CN110809810A
Application number: CN201880042876.9A
Authority: CN
Inventors: D·A·帕索斯; J·D·阿格列罗
Original assignee: Ioxus Inc
Current assignee: Ioxus Inc
Priority date: 2017-05-18
Filing date: 2018-05-18
Publication date: 2020-02-18
Also published as: WO2018213701A1; US20180337550A1; AU2018269939A1; EP3625812A1; KR20200008140A

Abstract

Systems, apparatuses, and methods are disclosed for operating a system that includes an energy storage device electrically coupleable to an external device having a first terminal and a second terminal and a switching device disposed between the energy storage device and the first terminal and/or the second terminal such that actuating the switching device either disconnects the energy storage device from the first terminal and/or the second terminal to prevent at least one of releasing energy from the energy storage device to the external device and charging energy from the external device to the energy storage device, or connects the energy storage device to the first terminal and the second terminal to allow at least one of supplying energy from the energy storage device to the external device and charging energy from the external device to the energy storage device.

Description

System, apparatus and method for secure energy storage

Cross Reference to Related Applications

This application claims priority rights under U.S. application No.62/507,998 entitled "SYSTEMS, APPARATUS, AND METHODS FOR SAFE ENERGY STORAGE", filed 2017, 5, month 18, under 35 u.s.c § 119(e), the disclosure of which is incorporated herein by reference in its entirety.

Technical Field

The present disclosure relates generally to systems, apparatuses, and methods for improving the safety of energy storage devices, and more particularly to electrical disconnects (disconnections) that electrically secure energy storage devices.

Background

A general trend in developing energy storage devices is to increase the energy density and power density of the devices in order to extend cycle life (e.g., smartphone battery life) and support applications with high power requirements (e.g., electric automobiles). The increase in energy and power density also creates a safety hazard. Accidental failure or short circuiting of these energy storage devices can lead to electrical explosions or release of large amounts of energy in a short period of time, thereby threatening not only the energy storage devices, but also nearby individuals (e.g., maintenance personnel) and property. For example, in an arc flash event where the temperature may reach or exceed 35,000 ° F (i.e., hotter than the surface of the sun), serious damage, fire, injury, and possibly even death may result. Existing safety measures are burdensome (e.g., time consuming and expensive) or impractical (e.g., reducing energy and power density), and thus do not satisfactorily address these safety concerns.

Disclosure of Invention

Systems, apparatuses, and methods for operating an energy storage device electrically coupleable to an external device by a first terminal and a second terminal operation, with a switching device disposed within a housing between the energy storage device and the first terminal and/or the second terminal, are disclosed. In some embodiments, actuating the switching device disconnects the energy storage device from the first terminal and/or the second terminal to prevent at least one of releasing energy from the energy storage device to the external device and charging energy from the external device to the energy storage device. In some embodiments, actuating the switching device connects the energy storage device to the first terminal and/or the second terminal to allow at least one of supplying energy from the energy storage device to the external device and charging energy from the external device to the energy storage device.

It should be appreciated that all combinations of the foregoing concepts and additional concepts discussed in greater detail below (provided that these concepts do not contradict each other) are considered to be part of the inventive subject matter disclosed herein. In particular, all combinations of claimed subject matter appearing at the end of this disclosure are considered part of the inventive subject matter disclosed herein. It should also be appreciated that terms explicitly employed herein, which may also appear in any disclosure incorporated by reference, should be given the most consistent meaning to the particular concepts disclosed herein.

Other systems, processes, and features will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, processes, and features be included within this description, be within the scope of the present invention, and be protected by the accompanying claims.

Drawings

Those skilled in the art will appreciate that the drawings are primarily for illustrative purposes and are not intended to limit the scope of the inventive subject matter described herein. The figures are not necessarily to scale; in some instances, various aspects of the subject matter disclosed herein may be shown exaggerated or enlarged in the drawings to facilitate an understanding of various features. In the drawings, like reference numbers generally indicate like features (e.g., functionally similar and/or structurally similar elements).

Fig. 1 is a schematic diagram of an energy storage system including a safety switch, according to some embodiments.

Fig. 2 is a schematic diagram of an energy storage system including a safety switch and a controller, according to some embodiments.

Fig. 3 is a schematic diagram of an energy storage system including a safety switch controlled by a microcontroller, according to some embodiments.

FIG. 4 is a schematic diagram of an energy storage system including a safety switch and a trickle charge switch, according to some embodiments.

Detailed Description

The present disclosure describes systems, apparatuses, and methods for improving the safety of energy storage devices, and more particularly, to safety disconnects for energy storage devices.

The increase in energy and power density of the energy storage device also creates a safety hazard. For example, supercapacitors have the advantage of charging and discharging large amounts of energy quickly in a short time. However, in the event of an accidental short circuit (i.e., when the current travels along an undesired path with very low resistance), this advantage may create a safety hazard that may produce, for example, an arc flash. Arc flashes are usually caused by human error, and 65% can occur when an operator is working on the switchgear. Traditional attempts to protect operators from arc flashes include equipping them with personal protective equipment, but this may be burdensome and inconvenient for the operator, or by replacing them with remote operators and/or robots, but this may be impractical or too expensive. Another way to protect operators from arc flash hazards is to power down the supercapacitor during access and/or maintenance. In some industrial applications, this step may require a large amount of coordination or may not be feasible at all. Accordingly, it is desirable to provide more efficient security protection for energy storage devices.

In response to the challenge of addressing safety hazards in an energy storage system, the techniques described herein employ a safety switch between the energy storage element (e.g., an internal electrode in an ultracapacitor) and any external terminals exposed to the ambient environment. In some embodiments, the safety switch may be manually closed to isolate the energy storage element from accidental shorting when a worker is required to work in proximity to the energy storage device. In some embodiments, the switch may be configured to automatically open in response to a change in an operating parameter, such as a surge in current or a large voltage drop. These techniques are convenient, cost effective, and suitable for use with various types of energy storage devices.

Fig. 1 illustrates a system 100 that may address, at least in part, safety concerns associated with electrical energy storage, in accordance with some embodiments. In fig. 1, the system 100 includes an energy storage device (e.g., a battery, an ultracapacitor, etc.) 110 that stores electrical energy. As shown in fig. 1, the energy storage device 110 may include a positive electrode 112, a negative electrode 114 (collectively referred to as internal electrodes 112, 114), an electrolyte 115 (also referred to as a dielectric layer or material) disposed in a space defined by the positive electrode 112 and the negative electrode 114, and a separator 116 disposed in the electrolyte 115 for allowing diffusion of ions rather than electrons. In addition to the energy storage device 110, the system 100 includes a safety switch 120 and a pair of

electrodes

130a and 130b (also referred to as

terminals

130a and 130 b). The energy storage device 110 is substantially enclosed in a housing 140 and is coupled to a pair of

electrodes

130a and 130b that are external to the housing 140 and thus collectively referred to as external electrodes or terminals 130. The terminals 130 serve as an interface for coupling the system 100 to deliver power to an external device (e.g., during discharge) or receive power from an external device (e.g., during charging). The terminal 130 is coupled to the energy storage device 110 via a safety switch 120, which safety switch 120 may be internal to the housing 140 and/or external to the housing 140 to allow operator access to control the safety switch 120. By closing the safety switch 120, the operator may disconnect the energy storage device 110 from the terminals 130 so that it may safely work with the system 100 or in the vicinity of the system 100. In some embodiments, the system 100 includes a safety switch 120 disposed inside the housing 140 and configured to be automatically actuated or activated in response to a command from a processor or controller.

Safety switch

Various types of switches may be used to construct the safety switch 120 shown in fig. 1. In some embodiments, the safety switch 120 comprises a toggle switch actuated by a lever angled in one of two or more positions. The toggle switch may be stopped in any of its lever positions, or may have an internal spring mechanism that resets the lever to a certain position, thereby achieving a "momentary" operation.

In some embodiments, the safety switch 120 comprises a push button switch. The push button switch may be a two-position device actuated by a push button that is depressed and released. The push button switch may have an internal spring mechanism for resetting the push button to a certain position (e.g., its "extended" or "un-depressed" position) for momentary operation. In some embodiments, the push button switch may be alternately turned on and off each time the push button is pressed. In other embodiments, the push button switch remains in a certain position (e.g., its "plugged in" or "pressed" position) until the button is pulled back. In some embodiments, the push button switch needs to be continuously held (i.e., in the "pressed" position) for a limited period of time to close the switch to avoid accidental activation of the switch. The limited period of time may be about 1 second to about 30 seconds (e.g., about 2 seconds, about 5 seconds, about 10 seconds, or about 15 seconds).

In some embodiments, the safety switch 120 includes a selector switch that can be actuated with a knob or lever to select one of two or more positions. The selector switch may be stopped in any of its positions or may contain an internal spring return mechanism for momentary operation.

In some embodiments, the safety switch 120 comprises a joystick switch that may be actuated by a lever that is free to move in more than one axis of motion. Depending on the way(s) in which the lever is pushed, one or more of several switch contact mechanisms may be actuated. In some embodiments, one or more of several switch contact mechanisms are actuated depending on how close the lever is pushed in either direction.

In some embodiments, the safety switch comprises a power Metal Oxide Semiconductor Field Effect Transistor (MOSFET), which is a three-terminal silicon device. A power MOSFET switch may operate by applying a signal to a gate that controls current conduction between a source and a drain. The current conduction capability can be as high as tens of amperes with breakdown voltage ratings of about 10V to over 1000V.

In some embodiments, the safety switch comprises an Insulated Gate Bipolar Transistor (IGBT), which is a three-terminal power semiconductor. IGBTs are known for high efficiency and moderate switching speeds.

In some embodiments, the safety switch includes a silicon carbide (SiC) power semiconductor that can reduce on-resistance by up to about two orders of magnitude compared to existing silicon devices.

In some embodiments, the safety switch includes a gallium nitride (GaN) device grown on top of a silicon substrate. The GaN device may behave like a silicon MOSFET. In some embodiments, the GaN device is a GaN transistor. The positive bias of the gate with respect to the source causes the device to turn on. When the bias is removed from the gate, electrons under the gate are scattered into the GaN, reforming the depletion region and again giving the device the ability to block voltage.

The default state of the safety switch may be on or off. In some embodiments, the safety switch is set to be in the connected state ("ON" state) unless the operator positively opens the safety switch. For example, the super capacitor battery may continuously power the external device unless and until operator intervention. In some embodiments, the safety switch is set to an open state ("OFF" state) unless the operator affirmatively connects the safety switch.

In some embodiments, the safety switch automatically opens when certain operating conditions of the energy storage device occur. For example, the system may include a thermometer to monitor the operating temperature of the energy storage device (e.g., ultracapacitor cell). The safety switch may automatically disconnect to protect the energy storage device or the external device if the temperature exceeds a threshold temperature. In another example, the current flowing through the wire connecting the internal electrodes and/or terminals is monitored such that the safety switch automatically opens if the current exceeds a threshold current.

Energy storage devices that may be used with some embodiments include, but are not limited to, ultracapacitor(s), and EDLC(s), all of which are used interchangeably throughout this disclosure. As described herein, an energy storage device may include one or more ultracapacitor cells disposed within a housing.

Energy storage devices that may also be used with some embodiments include, but are not limited to, primary batteries, Lithium Ion Capacitors (LiC), Lithium Ion Batteries (LiB), secondary (rechargeable) batteries, wet cell units, dry cell units, galvanic cell units, electrolytic cell units, fuel cell units, flow cell units, voltaic stacks, biological batteries, leaky acid cell units, daniel cell units, superconducting magnetic storage systems, and/or capacitors.

It is noted that fig. 1 shows only one supercapacitor cell 110, for illustration purposes only. In practice, the ultracapacitor system 100 may comprise a plurality of ultracapacitor cells. In some embodiments, the ultracapacitor system 100 comprises an array of ultracapacitor cells connected, for example, in series. In some embodiments, the ultracapacitor 100 includes an array of ultracapacitor cells in parallel with all positive electrodes connected to the external positive terminal 130a and all negative electrodes connected to the external negative terminal 130 b. In some embodiments, the ultracapacitor system 100 comprises a plurality of ultracapacitor cells connected in a hybrid configuration, wherein some of the cells are connected in series and some of the cells are connected in parallel.

System with safety switch and controller

Fig. 2 illustrates a schematic of a supercapacitor system 200 according to some embodiments, the supercapacitor system 200 including a supercapacitor cell 210 having a positive electrode 212, a negative electrode 214, an electrolyte 215 disposed in a space defined by the positive electrode 212 and the negative electrode 214, and a separator disposed in the electrolyte 215 that allows diffusion of ions rather than electrons. The supercapacitor system 200 also includes a safety switch 220, the safety switch 220 coupling the supercapacitor cell 210 to a pair of

external terminals

230a and 230b (collectively referred to as external electrodes 230 or terminals 230). The supercapacitor cell 210 and the safety switch 220 are substantially enclosed in a housing 240. A controller 250 disposed outside the housing 240 and operatively coupled to the safety switch 220 may be used to control the safety switch 220.

In some embodiments, the controller 250 is coupled to the safety switch 220 via a wire. In some embodiments, controller 250 is coupled to safety switch 220 via wireless communications including, but not limited to, Radio Frequency (RF) communications, WiFi, bluetooth, 3G, 4G, infrared communications, the internet, or any other means known in the art. In some embodiments, the safety switch 220 is controlled by the controller 250 via a relay to protect the operator from potential electric shock.

In some embodiments, the controller 250 is secured to a wall of the housing 240. In other embodiments, the controller 250 is removable and/or separate from the ultracapacitor cells 210. The controller 250 may be mobile or portable. For example, an operator may remove and/or carry the controller 250 separate from the ultracapacitor cells 210, but still be able to control and interact with the ultracapacitor system 200 while operating in the vicinity of the ultracapacitor cells 210. In these examples, the controller 250 may be coupled to the safety switch 220 via wired or wireless communication.

In some embodiments, the safety switch 220 may be configured to provide enhanced safety during operation via one or more of the following features. In some embodiments, the security switch 220 is integrated within the housing 240, which may require some authorization to open. Thus, the safety switch 220 can only be disabled by authorized personnel. In some embodiments, the safety switch 200 may be actuated only via a wireless signal from the controller 250. This feature may avoid accidental actuation of the safety switch 220. Integrating the safety switch 220 within the housing 240 at the time of manufacture may provide advantages of lower cost and smaller form factor than adding the safety switch later. In this manner, the housing 240 isolates and seals both the ultracapacitor cell 210 and the safety switch 220 from the external environment.

In some embodiments, the safety switch 220 is substantially enclosed within the housing and does not include an external actuator to disconnect the electrical connection between the ultracapacitor cell 210 and at least one of the first terminal 230a and the second terminal 230 b. In other words, the safety switch 220 integrated within the housing 240 cannot be disconnected or connected by a mechanical or electrical actuator external to the housing 240. In these embodiments, the safety switch may be engaged or disengaged by a wireless signal transmitted to a controller 250 located within the housing 240. These embodiments prevent an unauthorized operator who does not have access to the wireless transmitter from accidentally or intentionally engaging or disengaging the security switch 220.

In some embodiments, an additional controller (not shown) may be included within the housing 240 and communicate with the external controller 250 to control the operation of the safety switch 220 (see, e.g., fig. 3).

In some embodiments, the controller 250 is configured to actuate the safety switch 220 to disconnect the supercapacitor cell 210 from the terminal 230a in response to an overcharged state of the supercapacitor cell 210. In some embodiments, any other internal/external fault may also trigger the controller 250 to disengage the safety switch 220.

In some embodiments, the system 200 further comprises a sensor (not shown) operably coupled to the controller 250 to measure the ambient temperature surrounding the ultracapacitor cell 210. The controller 250 is configured to actuate the safety switch 220 to disconnect the ultracapacitor cell 210 from the terminal 230a in response to the ambient temperature being greater than a threshold. In some embodiments, the sensor is configured to measure the internal case temperature, and the controller 250 is configured to actuate the safety switch 220 to disconnect the ultracapacitor cell 210 from the terminal 230a in response to the internal case temperature being greater than a threshold value.

Fig. 3 is a schematic diagram of an ultracapacitor system 300 including a safety switch 320 controlled by a microcontroller 360 according to some embodiments. The system 300 includes a series of ultracapacitors 310 enclosed by a housing 340. Two terminals 330a and 330b operatively coupled to a series of ultracapacitors 310 are disposed outside of housing 340 (e.g., on an outer surface of housing 340) and may be electrically coupled to a bank of ultracapacitors 310 via switch 320. More specifically, the bank of ultracapacitors 310 has a first side 315a electrically coupled to a positive terminal 330a via a switch 320, and the bank has a second side 315b directly coupled to a negative terminal 330 b.

A power source or battery 370 is connected to the two terminals 330a and 330b and a DC-DC converter 350 is also enclosed within the housing to facilitate energy transfer between the supercapacitor 310 and the power source or battery 370. The DC-DC converter 350 may have an input 352 electrically coupled to the positive terminal 330a, the positive terminal 330a being electrically coupled to a power source or battery 370. The DC-DC converter 350 also has an output 354 electrically coupled to the first side 315a of the bank of ultracapacitors 310. Further, the negative terminal 330b, the microcontroller 360, the DC-DC converter 350, and the second side 315b of the bank of ultracapacitors 310 may be connected to a common ground 380. The switch 320 includes a pair of MOSFETs 322a and 322b to allow bi-directional switching between the supercapacitor 310 and the power supply or battery 370. For example, turning off one MOSFET (connecting the gate of the MOSFET to the source, i.e., V)_gs0) may prevent current from flowing from the power supply or battery 370 to the supercapacitor 310, and turning off another MOSFET (e.g., 322b) may prevent current from flowing from the supercapacitor 310 to the power supply or battery 370. In some embodiments, microcontroller 360 is also controlled by an external device (e.g., a controller) or operator via wireless communication. In these embodiments, microcontroller 360 may still automatically open switch 320 in response to, for example, an internal/external fault condition to provide enhanced safety.

As shown in fig. 3, the supercapacitor 310, the switch 320, the DC-DC converter 350, and the microcontroller 360 may all be enclosed in a housing 340 to provide an integrated energy module with enhanced safety features. The housing 340 may be sealed such that only authorized personnel (e.g., maintenance personnel of the manufacturer) may open the housing 340 and disable the switch 320. In other words, the end user may not be able to select to open the housing 340 and/or disable the switch 320.

In some embodiments, microcontroller 360 is powered by supercapacitor 310. In some embodiments, microcontroller 360 is powered by a power supply or battery 370. In some embodiments, microcontroller 360 may be powered by an external power source via, for example, wireless energy transfer.

In some embodiments, the DC-DC converter 350 may receive energy from a power source or battery 370 to charge the supercapacitor 310. The DC-DC converter 350 is also operatively coupled to a microcontroller 360, and the microcontroller 360 can provide control signals to the DC-DC converter 350 to control the charging process. In some embodiments, microcontroller 360 may control DC-DC converter 350 to charge only supercapacitor 310 and not power source or battery 370 (i.e., unidirectional energy transfer from power source or battery 370 to supercapacitor 310). In some embodiments, microcontroller 360 may control the charge rate based on the state of the power source or battery 370.

In some embodiments, microcontroller 360 is configured to open switch 320 to prevent supercapacitor 310 from accepting any energy when power source or battery 370 is not connected. In some embodiments, microcontroller 360 is configured to open switch 320 if a fault is detected. In some embodiments, the fault includes an internal fault, such as an overcharge condition. In some embodiments, the internal fault includes a fault in the DC-DC charger 350 or a fault in the microcontroller 360.

In some embodiments, the fault comprises an external fault, such as an ambient temperature above a threshold. In some embodiments, the external fault is an over-current condition caused by an external short circuit, an over-voltage applied to terminals 330a and 330b, a reverse bias voltage applied to terminals 330a and 330b, or an invalid control input.

In some embodiments, the system 300 includes a string of supercapacitors 310 in series, each of which may be a high specific capacitance electrochemical capacitor that electrostatically stores energy. A typical supercapacitor 310 has a capacitance value of about 10,000 times that of an electrolytic capacitor, an energy density of about 10% of a conventional battery, and a power density of up to 100 times that of the battery. This allows the supercapacitor 310 to have faster charge and discharge cycles than conventional batteries. It also allows the supercapacitor 310 to have an extremely long cycle life compared to a battery.

Each supercapacitor 310 may be charged to a predetermined level of each cell voltage. As a specific example, the super capacitor 310 may be charged to support 2.7V/cell. The voltage per cell value may automatically shift higher (e.g., 3.0V/cell) when low temperatures are reached (e.g., 0 ° F), and even higher voltage per cell (e.g., 3.3V/cell) when the temperature drops even lower (e.g., below-20 ° F). In some embodiments, the temperature may be measured by a sensor (not shown in fig. 3). In some embodiments, each pack of ultracapacitors 310 may use a DC-DC converter (e.g., a 500W DC-DC converter) 350, which may be set at the factory to a voltage range, for example, from 16.2V to 24V. The DC-DC converter 350 may have the appearance of a boost or single-ended primary inductor converter (SEPIC). Additional details can be found in U.S. patent publication No.2016/0243960a1, entitled "ENGINE START AND BATTERY SUPPORT MODULE," the disclosure of which is incorporated by reference herein in its entirety.

FIG. 4 is a schematic diagram of an ultracapacitor system 400, the ultracapacitor system 400 including control electronics 422 and a trickle charge switch 424 to allow for trickle charging, i.e., charging at a slow rate or charging at no load at a rate equal to its self-discharge rate. The system 400 includes a series of ultracapacitors 410 enclosed in a housing 440, and the ultracapacitors 410 have two

terminals

430a and 430b disposed on an outer surface of the housing 440. The control electronics 422 includes a voltage controlled switch that enables and disables the safety switch 428 and the trickle charge switch 424. In some embodiments, the safety switch 428 is an electromechanical relay. A power source or battery 470 may be operatively connected to the two

terminals

430a and 430 b. A safety switch 428 is operatively coupled to the supercapacitor 410 and the power source or battery 470. In operation, opening safety switch 428 disconnects supercapacitor 410 from terminal 430b (and correspondingly operably connected to power source or battery 470), thereby electrically securing the energy storage device.

The trickle charge switch 424 is actuated by the control electronics 422 to allow the super capacitor 410 to be charged from the power source or battery 470 so that when the voltage is at or equal to a predetermined threshold, the safety switch 428 may be engaged to prevent a current surge. The trickle charge switch 424 includes a diode 427 for blocking reverse voltages and a MOSFET that is actuated when both the power source (e.g., battery 470) and the supercapacitor 410 are coupled. The trickle charge continues until the voltage difference between the super capacitor 410 and the battery 470 converges and the safety switch 428 engages. A resistor 426 may also be included in the ultracapacitor system 400 to regulate current flow during trickle charging.

Although the present disclosure is described primarily in terms of a supercapacitor, according to some embodiments, various other types of energy storage devices may benefit from safety switches, including but not limited to conventional capacitors, electrochemical cells, and fuel cell units.

Conventional capacitors typically include two conductive electrodes (also referred to as a capacitor bank) separated by an insulating dielectric material (e.g., air or other dielectric material). When a voltage is applied to the capacitor, positive charges accumulate on the surface of one electrode, and negative charges accumulate on the surface of the other electrode. The insulating dielectric material separates the positive and negative charges, thereby creating an electric field that allows the capacitor to store energy.

The capacitance C of the capacitor is defined as C ═ Q/V, where Q is the stored charge and V is the applied voltage. Generally, a high capacitance allows the capacitor to store more energy when the same voltage is applied across the capacitor. For a conventional capacitor, the capacitance C may be defined as C ═ epsilon₀ε_rA/D, where A is the surface area of each electrode, D is the distance between the electrodes, ε₀Is the dielectric constant (or "permittivity") of free space and ε_rIs the dielectric constant of the insulating material between the electrodes.

Of energy storage and discharge capacity of capacitorsCharacterized by its energy density and power density, which can be calculated as the total energy or power divided by the mass or volume of the capacitor. The total energy E stored in the capacitor can be calculated as E-1/2 CV²It is proportional to the capacitor C. The power P of the capacitor is typically the energy consumed per unit time. To determine P of the capacitor, the capacitor can be viewed as a circuit in series with an external "load" resistance R. The internal components of the capacitor (e.g., current collectors, electrodes, and dielectric material) also contribute to resistance, which can be measured collectively by the Equivalent Series Resistance (ESR) of the capacitor. Maximum power P of the capacitor when measured at matched impedance (R ═ ESR)_maxCan pass through P_max＝V²V (4ESR) indicates that ESR may be the limiting factor for the maximum power (and therefore maximum power density) of the capacitor.

Conventional capacitors may have a higher power density, but a lower energy density, compared to electrochemical cells and fuel cell units. In other words, the battery may store more total energy, but take longer to deliver energy and charge the battery. Capacitors, on the other hand, can store less energy per unit mass or volume, but release energy quickly to produce a large amount of power.

To address the shortcomings of conventional capacitors (low energy density) and batteries (low power density), supercapacitors use electrodes with a large surface area a (e.g., porous electrodes) and a short distance D between the capacitor banks (e.g., less than 1 μm or even 1 nm). The large surface area may result in greater capacitance, thereby increasing the energy density of the ultracapacitor, while the short distance between capacitor banks may result in lower ESR, thereby increasing the power density of the ultracapacitor. In addition, supercapacitors have several other advantages over electrochemical cells and fuel cell units, including higher power density, shorter charge times, and longer cycle life and shelf life. However, as noted above, supercapacitors may also pose an increased safety hazard to operators, and it is desirable to provide a viable and efficient safety measure when using supercapacitors.

Referring back to fig. 1 and 2, inIn some embodiments, the ultracapacitor cell 110 shown in fig. 1 (or the ultracapacitor cell 210 in fig. 2) comprises an Electrochemical Double Layer Capacitor (EDLC). In general, EDLCs store charge electrostatically (also referred to as non-faradaic storage) and there is no charge transfer between the internal electrodes 112, 114 (or

internal electrodes

212 and 214 in fig. 2) and the electrolyte 115 (or electrolyte 215 in fig. 2). More specifically, EDLCs may utilize an electrochemical double layer of charge to store energy. When a voltage is applied across the EDLC, positive ions in the electrolyte 115 diffuse across the separator 116 toward the negative electrode 114, while negative ions or electrons in the electrolyte 115 drift toward the positive electrode 112. Further, the

internal electrodes

112, 114 are fabricated such that there is no recombination of charges. Thus, a double layer charge can be generated on each electrode. The combination of the double layers, the increase in the surface area of the

internal electrodes

112, 114, and the reduction in the distance between the

internal electrodes

112, 114, allow the EDLC to achieve a higher energy density than conventional capacitors. Because there are no chemical or compositional changes associated with non-faradaic processes at the

inner electrodes

112, 114, charge storage in EDLCs is highly reversible, allowing for high cycling stability. For example, EDLCs can typically range up to 10⁶Operating at steady performance characteristics for one cycle.

The

inner electrodes

112, 114 may comprise various materials. In some embodiments, the

internal electrodes

112, 114 comprise one or more carbon-based materials, which have the advantages of relatively high surface area, low cost, and mature manufacturing techniques.

In some embodiments, the

inner electrodes

112, 114 comprise activated carbon having a porous structure. The activated carbon may include micropores having a characteristic diameter of less than about 2 nm. In some embodiments, the activated carbon includes mesopores having a characteristic diameter of less than about 50 nm. In other embodiments, the activated carbon includes macropores having a characteristic diameter greater than about 50 nm. The activated carbon may include a combination of micropores, mesopores, and/or macropores. In general, larger pore sizes may result in higher power densities, while smaller pore sizes may result in higher energy densities. Thus, in practice, the distribution of pore sizes and the distribution of activated carbon electrodes may depend on the desired energy density or power density of the resulting supercapacitor.

In some embodiments, the

inner electrodes

112, 114 comprise a carbon aerogel, which may be formed from a continuous network of conductive carbon nanoparticles having interspersed mesopores. Carbon aerogels generally do not require additional binders in applications due to their continuous structure and ability to chemically bond to a current collector (not shown in fig. 1). Thus, electrodes made from carbon aerogel can have lower ESR, and therefore higher power density, than activated carbon.

In some embodiments, the

inner electrodes

112, 114 comprise Carbon Nanotubes (CNTs). In these examples, the

internal electrodes

112, 114 may be grown as tangled CNT mats with an open and accessible network of mesopores. Unlike other carbon-based electrodes, the mesopores in the carbon nanotube electrode can interconnect to achieve a continuous charge distribution that can utilize nearly all of the available surface area of the

inner electrodes

112, 114. Thus, the effective surface area of the

inner electrodes

112, 114 may be further increased, thereby increasing the capacitance of the resulting supercapacitor. In addition, carbon nanotube electrodes can also have a lower ESR than activated carbon, since ions diffuse more readily into the mesoporous network. In some embodiments, the nanotubes used in the

inner electrodes

112, 114 comprise single-walled CNTs having relatively high conductivity and possibly a larger stability voltage window.

In some embodiments, CNTs are grown directly on the current collectors to form the

internal electrodes

112, 114. In some embodiments, CNTs are cast into a colloidally suspended thin film, which can then be transferred to a current collector to form the

internal electrodes

112, 114.

In some embodiments, the

inner electrodes

112, 114 comprise graphene. Graphene may be synthesized by chemically reducing graphene oxide using hydrazine. Graphene may have a relatively high accessible surface area (e.g., about 2600m due to lack of agglomeration)²Per gram), high conductivity (e.g., about 100S/m), and excellent chemical stability. In some embodiments, the

inner electrodes

112, 114 comprise a conductive polymer.

In some embodiments, the

internal electrodes

112, 114 comprise transition metal oxides, which may have a layered structure and adopt multiple oxidation states. The electrochemical behavior of the oxide can be pseudo-capacitive in nature due to highly reversible surface chemical reactions and/or extremely fast and reversible lattice intercalation. In some embodiments, the

inner electrodes

112, 114 comprise ruthenium oxide and/or manganese oxide.

In some embodiments, the

inner electrodes

112, 114 include a composite of transition metal oxides and/or other electrode materials, such as conductive polymers and/or carbon-based materials, to maintain performance while reducing manufacturing costs. In some embodiments, the

inner electrodes

112, 114 comprise ruthenium dioxide, which may be electrodeposited into poly (3, 4-ethylenedioxythiophene). In some embodiments, the

inner electrodes

112, 114 comprise manganese oxide and a conductive polymer such as polypyrrole deposited on the CNTs to increase conductivity.

In some embodiments, the

inner electrodes

112, 114 comprise a nitride and/or sulfide, such as molybdenum nitride. In some embodiments, the nitride is synthesized by temperature programmed nitridation of various oxides, such as molybdenum and/or vanadium. In some embodiments, the

inner electrodes

112, 114 comprise synthetic Vanadium Nitride (VN) nanoparticles that are subsequently passivated by a two-step ammonolysis process. In some embodiments, the

internal electrodes

112, 114 comprise copper and cobalt sulfide films.

The electrolyte 115 in the ultracapacitor cell 110 can include various materials. In some embodiments, electrolyte 115 comprises an aqueous electrolyte, such as sulfuric acid (H)₂SO₄) And/or potassium hydroxide (KOH). In some embodiments, electrolyte 115 comprises an organic electrolyte, such as acetonitrile. In some embodiments, electrolyte 115 comprises tetraethylammonium tetrafluoroethanesulfonate (Et) in acetonitrile₄NBF₄). In some embodiments, electrolyte 115 includes an organic acid (CF)₃COOH) and a supporting electrolyte of tetramethylammonium methanesulfonate. Aqueous electrolytes can have lower ESR and lower minimum pore size requirements than organic electrolytes. However, aqueous electrolytes may also have lower breakdown voltages. Indeed, the trade-off between capacitance, ESR and voltage may be taken into account when selecting the electrolyteIt is also beneficial to use the method.

The separator 116 in the supercapacitor cell 110 allows ions to pass through but not electrons, thereby avoiding direct discharge between the

internal electrodes

112, 114. In some embodiments, separator 116 comprises a membrane, which may be composed of a synthetic polymer (i.e., ionomer) having ionic properties, such as

PFSA membranes (available from DuPont, Wilmington, DE) may include hydrophobic Teflon^TMMain and side chains and hydrophilic sulfonic acid (-SO3H) groups. In some embodiments, separator 116 comprises polyvinyl alcohol, which has relatively good mechanical strength and low cost. In some embodiments, separating member 116 comprises lauroyl chitosan, which has a relatively high level of mechanical strength and ionic liquid retention.

In some embodiments, separator 116 is made of a blend of polymer electrolyte polyvinyl alcohol (PVA) (e.g., about 70%) and phosphoric acid (H)₃PO₄) (e.g., about 30%) of the resulting mixture is immersed in a solution of a combination of poly (methyl methacrylate) and lauroyl chitosan (PLC) for use in a supercapacitor. In some embodiments, the separator 116 is made of polypropylene.

In some embodiments, the supercapacitor 110 comprises a pseudocapacitor. In general, pseudocapacitors store charge via a faraday process that involves charge transfer between

internal electrodes

112, 114 and electrolyte 115. Charge transfer can be achieved by, for example, electro-adsorption, reduction-oxidation reactions, and/or intercalation processes, among others. These faraday processes can enable pseudocapacitors to achieve higher capacitance and energy densities.

In some embodiments, the

internal electrodes

112, 114 used in the pseudocapacitor comprise a conductive polymer, which may have high capacitance and conductivity in addition to low ESR and cost. In some embodiments, the

internal electrodes

112, 114 have an n/p-type polymer configuration, wherein the negative electrode 114 comprises a negatively charged (n-doped) conductive polymer and the positive electrode 112 comprises a positively charged (p-doped) conductive polymer.

In some embodiments, the

inner electrodes

112, 114 in the pseudocapacitor comprise a metal oxide such as ruthenium oxide due to its high capacitance. The capacitance of ruthenium oxide can be achieved by inserting and removing or intercalating protons in its amorphous structure. In its hydrated form, ruthenium oxide can have a greater capacitance than carbon-based and conductive polymer materials. Furthermore, the ESR of the hydrated ruthenium oxide can be lower than other electrode materials.

In some embodiments, the

inner electrodes

112, 114 comprise nanoparticles. In some embodiments, mesopores and crystallinity may be retained in the nanoparticles to obtain maximum pseudocapacitance. The increase in charge storage capacity may depend on the porosity of the outer wall. The mesopores and resulting nanoparticle properties can create a large surface and be easily inserted. At the same time, crystallinity may be maintained to reduce grain boundaries and associated mass transport effects. In some embodiments, the

inner electrodes

112, 114 comprise TiO synthesized by a templating method₂Or MoO₃. Templated synthesized materials may have more developed and ordered pores than sol-gel derived materials, thereby allowing easy diffusion of electrolyte into the internal pores and resulting in increased capacitance and intercalation.

In some embodiments, the ultracapacitor cell 110 includes a hybrid capacitor that can store charge using both faradaic and non-faradaic processes. Hybrid capacitors can achieve high energy and power densities without sacrificing cycling stability and affordability.

In some embodiments, the

internal electrodes

112, 114 comprise composite electrodes in order to form a hybrid capacitor. The composite electrode may include a carbon-based material and/or a metal oxide material with a conductive polymer. The carbon-based material may promote the formation of a capacitive double-layer charge and provide a high surface area backbone, thereby increasing the contact between the deposited pseudocapacitive material and the electrolyte 115. The pseudocapacitive material may further increase the capacitance of the composite electrode by faradaic reactions.

In some embodiments, the

inner electrodes

112, 114 comprise composite electrodes composed of carbon nanotubes and a conductive polymer (e.g., polypyrrole). The combination may have a higher capacitance than electrodes based on pure carbon nanotubes or electrodes based on pure polypyrrole polymers.

In some embodiments, ultracapacitor cell 110 includes an asymmetric configuration that combines faradaic and non-faradaic processes by coupling EDLC electrodes with pseudocapacitor electrodes. The negative electrode 114 may comprise an activated carbon electrode, and/or the positive electrode 112 may comprise a conductive polymer electrode.

In some embodiments, the supercapacitor 110 comprises a battery-type configuration that couples two different types of electrodes in a single supercapacitor cell. Battery-type hybrid capacitors typically include supercapacitor electrodes with battery electrodes. In some embodiments, the battery electrode includes nickel hydroxide, lead dioxide, and/or lithium titanate (e.g., Li)₄Ti₅O₁₂). In some embodiments, the supercapacitor electrode comprises activated carbon or any other material described herein.

While various inventive embodiments have been described and illustrated herein, those of ordinary skill in the art will readily envision a variety of other means and/or structures for performing the functions and/or obtaining the results and/or one or more of the advantages described herein, and each of such variations and/or modifications is deemed to be within the scope of the inventive embodiments described herein. More generally, those skilled in the art will readily appreciate that all parameters, dimensions, materials, and configurations described herein are meant to be exemplary and that the actual parameters, dimensions, materials, and/or configurations will depend upon the specific application or applications for which the teachings of the present invention is/are used. Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific inventive embodiments described herein. It is, therefore, to be understood that the foregoing embodiments are presented by way of example only and that, within the scope of the appended claims and equivalents thereto, inventive embodiments may be practiced otherwise than as specifically described and claimed. Inventive embodiments of the present disclosure are directed to each individual feature, system, article, material, kit, and/or method described herein. In addition, any combination of two or more such features, systems, articles, materials, kits, and/or methods, if such features, systems, articles, materials, kits, and/or methods are not mutually inconsistent, is included within the inventive scope of the present disclosure.

The above-described embodiments may be implemented in any of numerous ways. For example, although the embodiments herein describe electrochemical devices such as, for example, lithium ion batteries, the systems, methods, and principles described herein are applicable to all devices that contain electrochemically active media. Any electrode and/or device (including at least an active material (source or well of charge carriers), a conductive additive, and an ionically conductive medium (electrolyte), such as, for example, a battery, a capacitor, an electric double layer capacitor (e.g., a supercapacitor), a pseudocapacitor, etc.) is within the scope of the present disclosure. Further, embodiments may be used with non-aqueous electrolyte and/or aqueous electrolyte battery chemistries.

In another example, embodiments may be implemented using hardware, software, or a combination thereof. When implemented in software, the software code can be executed on any suitable processor or collection of processors, whether provided in a single computer or distributed among multiple computers. Additionally, it should be appreciated that a computer may be implemented in any of a variety of forms, such as a rack-mounted computer, a desktop computer, a laptop computer, or a tablet computer. Further, a computer may be embedded in a device not normally considered a computer but having suitable processing capabilities, including a Personal Digital Assistant (PDA), a smart phone, or any other suitable portable or fixed electronic device.

In addition, a computer may have one or more input and output devices. These devices may be used, among other things, to present a user interface. Examples of output devices that can be used to provide a user interface include printers or display screens for visual presentation of output and speakers or other sound generating devices for audible presentation of output. Examples of input devices that may be used for the user interface include keyboards, and pointing devices, such as mice, touch pads, and digitizing tablets. As another example, a computer may receive input information through speech recognition or other audible format.

Such computers may be interconnected by one or more networks IN any suitable form, including as a local area network or a wide area network (such as an enterprise network), and as an Intelligent Network (IN) or the Internet. Such networks may be based on any suitable technology and may operate according to any suitable protocol and may include wireless networks, wired networks, or fiber optic networks.

The various methods or processes outlined herein (e.g., in designing and manufacturing the above-disclosed retention/delivery structures) may be coded as software that is executable on one or more processors that employ any one of a variety of operating systems or platforms. Further, such software may be written using any of a number of suitable programming languages and/or programming or scripting tools, and also may be compiled as executable machine language code or intermediate code that is executed on a framework or virtual machine.

Moreover, various inventive concepts may be embodied as one or more methods, examples of which have been provided. The actions performed as part of the method may be ordered in any suitable way. Accordingly, embodiments may be constructed in which acts are performed in an order different than illustrated, which may include performing some acts concurrently, even though shown as sequential acts in illustrative embodiments.

All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety.

As defined and used herein, all definitions should be understood to control dictionary definitions, definitions in documents incorporated by reference, and/or ordinary meanings of the defined terms.

As used herein in the specification and claims, the indefinite articles "a" and "an" should be understood to mean "at least one" unless explicitly indicated to the contrary.

As used herein in the specification and in the claims, the phrase "and/or" should be understood to mean "either or both" of the elements so connected, i.e., the elements present in some cases combined and in other cases separated. Multiple elements listed with "and/or" should be interpreted in the same manner, i.e., "one or more" of the elements so combined. In addition to elements specifically identified by the "and/or" clause, other elements may optionally be present, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, when used in conjunction with an open language such as "including," references to "a and/or B" may, in one embodiment, refer to only a (optionally including elements other than B); in another embodiment, only B (optionally including elements other than a); in yet another embodiment, refer to both a and B (optionally including other elements); and so on.

As used herein in the specification and claims, "or" should be understood to have the same meaning as "and/or" as defined above. For example, when separating items in a list, "or" and/or "should be interpreted as being inclusive, i.e., including at least one of multiple elements or lists of elements, but also including more than one, and optionally, including additional unlisted items. Only terms explicitly indicating the contrary, such as "one of only …" or "exactly one of …," or "consisting of …" when used in the claims, will refer to including exactly one of a plurality or list of elements. In general, as used herein, the term "or" as used herein, when preceded by an exclusive term (such as "any one," "one of …," "only one of …," or "exactly one of …") is to be construed merely as indicating an exclusive substitution (i.e., "one or the other but not both"). "consisting essentially of …" when used in the claims shall have its ordinary meaning as used in the patent law field.

As used herein in the specification and claims, the phrase "at least one," when referring to a list of one or more elements, should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each element specifically recited within the list of elements and not excluding any combinations of elements in the list of elements. This definition also allows that elements may optionally be present other than the elements specifically identified within the list of elements referred to by the phrase "at least one," whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, "at least one of a and B" (or, equivalently, "at least one of a or B," or, equivalently, "at least one of a and/or B") can, in one embodiment, refer to at least one, optionally including more than one, a, wherein B is not present (and optionally including elements other than B); in another embodiment, to at least one, optionally including more than one, B, where a is not present (and optionally includes elements other than a); in yet another embodiment, to at least one, optionally including more than one, a, and at least one, optionally including more than one, B (and optionally including other elements); and so on.

In the claims, as well as in the specification above, all transitional phrases such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," "having," and the like are to be understood to be open-ended, i.e., to mean including but not limited to. Only the transition phrases "consisting of …" and "consisting essentially of …" will be closed or semi-closed transition phrases, respectively, as set forth in the united states patent office patent examination program manual 2111.03 section.

Claims

1. A system, comprising:

an energy storage device substantially enclosed in the housing;

first and second terminals for electrically coupling the energy storage device with an external device, the first and second terminals being external to the housing; and

a switching device substantially enclosed within the housing for controlling electrical connection between the energy storage device and at least one of the first terminal and the second terminal, the switching device being operably disposed between the energy storage device and at least one of the first terminal and the second terminal.

2. The system of claim 1, wherein the energy storage device comprises one or more of an ultracapacitor, an EDLC, and an ultracapacitor.

3. The system of claim 1, wherein said electrical energy storage device comprises a battery.

4. The system of claim 1, wherein the switching device is solid state.

5. The system of claim 1, wherein the switching device comprises a Metal Oxide Semiconductor Field Effect Transistor (MOSFET).

6. The system of claim 1, wherein the switching device substantially enclosed within the housing does not include an external actuator to break an electrical connection between the energy storage device and at least one of the first terminal and the second terminal.

7. The system of claim 1, further comprising:

a controller operatively coupled to the switching device for controlling the switching device.

8. The system of claim 7, wherein the controller is substantially enclosed in the housing.

9. The system of claim 7, wherein the controller is operatively coupled to the switching device via one or more of wired and wireless communication.

10. The system of claim 7, wherein the switching device is configured to be actuated only in response to a wireless control signal.

11. The system of claim 7, wherein the controller is operatively coupled to the switch via bluetooth communication.

12. The system of claim 11, wherein the controller is further configured to receive status information about the energy storage device via the bluetooth communication.

13. The system of claim 7, wherein the controller is configured to actuate the switching device to disconnect the energy storage device from at least one of the first terminal and the second terminal in response to an overcharge condition of the energy storage device.

14. The system of claim 7, further comprising:

at least one sensor operably coupled to the controller to measure an ambient temperature surrounding the energy storage device, wherein the controller is configured to actuate the switching device to disconnect the energy storage device from at least one of the first terminal and the second terminal in response to the ambient temperature being greater than a threshold.

15. The system of claim 7, further comprising:

at least one sensor operably coupled to the controller to measure an internal case temperature, wherein the controller is configured to actuate the switching device to disconnect the energy storage device from at least one of the first terminal and the second terminal in response to the internal case temperature being greater than a threshold value.

16. The system of claim 1, wherein the energy storage device comprises an ultracapacitor, and the external device comprises a battery.

17. The system of claim 16, further comprising:

a DC-DC converter operatively coupled to the ultracapacitor and the battery configured to facilitate energy transfer between the battery and the ultracapacitor.

18. The system of claim 16, wherein the switching device comprises two or more MOSFETs.

19. The system of claim 16, further comprising:

a controller operatively coupled to the switching device for controlling the switching device, the controller configured to selectively actuate the switching device to disconnect the energy storage device from at least one of the first terminal and the second terminal.

20. The system of claim 16, wherein the controller is powered by at least one of the ultracapacitor or the energy storage device.

21. The system of claim 16, further comprising:

a trickle charge switch electrically coupled to the ultracapacitor and the battery and configured to charge the ultracapacitor to a predetermined threshold.

22. The system of claim 21, wherein the trickle charge switch comprises a MOSFET.

23. A method of operating a system, the system comprising: an energy storage device comprising a housing; a first terminal and a second terminal for electrically coupling the energy storage device with an external device; and a switching device substantially enclosed within the housing and operably disposed between the energy storage device and at least one of the first terminal and the second terminal, the method comprising actuating the switching device to cause at least one of:

disconnecting the energy storage device from at least one of the first terminal and the second terminal to prevent at least one of providing energy from the energy storage device to the external device and charging energy from the external device to the energy storage device; and

connecting the energy storage device to at least one of the first terminal and the second terminal to enable at least one of providing energy from the energy storage device to the external device and charging energy from the external device to the energy storage device.

24. The method of claim 23, wherein the energy storage device comprises one or more of an ultracapacitor, an EDLC, and an ultracapacitor.

25. The method of claim 23 wherein said electrical energy storage device comprises a battery.

26. The method of claim 23, wherein the switching device is solid state.

27. The method of claim 23, wherein the switching device comprises a Metal Oxide Semiconductor Field Effect Transistor (MOSFET).

28. The method of claim 23, further comprising:

29. The method of claim 28, wherein the controller is substantially enclosed within the housing.

30. The method of claim 28, wherein the controller is operatively coupled to the switching device via one or more of wired and wireless communication.

31. The method of claim 28, wherein the controller is operatively coupled to the switch via bluetooth communication.

32. The method of claim 31, wherein the controller is further configured to receive status information about the energy storage device via the bluetooth communication.

33. The method of claim 28, wherein the controller is configured to actuate the switching device to disconnect the energy storage device from at least one of the first terminal and the second terminal in response to an overcharge condition of the energy storage device.

34. The method of claim 28, wherein the controller is configured to actuate the switching device to disconnect the energy storage device from at least one of the first terminal and the second terminal in response to an ambient temperature being greater than a threshold.

35. The method of claim 28, wherein the controller is configured to actuate the switching device to disconnect the energy storage device from at least one of the first terminal and the second terminal in response to an internal housing temperature being greater than a threshold value.

36. A method of operating a system, the system comprising: an energy storage device comprising a housing; a first terminal and a second terminal configured to be electrically coupled to the energy storage device; and a switching device substantially enclosed within the housing and operably disposed between the energy storage device and at least one of the first terminal and the second terminal, the method comprising:

electrically coupling the first and second terminals to an external device such that at least one of energy is provided from the energy storage device to the external device and energy is charged from the external device to the energy storage device; and

actuating the switching device to disconnect the energy storage device from at least one of the first terminal and the second terminal to electrically secure the energy storage device.